基于Z-buffer算法优化的大型变电站场景模型快速线消隐方法

针对现有三维模型消隐方法面向大规模三维场景模型应用中存在的计算复杂、耗时长等缺陷, 本文提出了基于改进 Z-buffer 算法对大型变电站场景消隐的快速可视化方法。首先,为了简化计算,将场景模 型数据整合并重构;其次,通过透视投影变换将变电场景模型像素化;进一步,基于 Z-buffer 算法高效的像素 化计算特性提出了快速模型筛选方法,从而得到变电场景的子模型遮挡关系。最后,实验中将所得遮挡关系列 表融合现有消隐算法,结果表明本文提出的方法能够大幅度提升消隐的运算性能。     

视频图像在三维模型中的渲染

视频监控是大型安防工作中最重要的一个环节,传统的视频监控系统展示给用户的只是独立的二维平面图像,图像脱离环境,整体性不足,为了解决该问题,提出了将视频图像渲染显示于三维模型的思路.研究了纹理映射技术并结合视频图像渲染的特殊性分析研究了Z缓冲算法、Shadow map算法,根据实际应用提出Extend Shadow map算法以实现将视频图像与三维场景无缝贴合.实验结果表明,视频图像渲染显示于三维模型中所体现的优越性.     

用于分析电磁散射的多层Z缓冲器技术

本文提出了一种用于分析电磁散射的多层Ｚ缓冲器技术，它使计算机图形学与电磁散射分析相结合，能有效地解决复杂物体电磁散射分析中的隐藏面消除问题和多次散射计算的射线跟踪问题，从而使复杂物体电磁散射的分析和计算更为精确，而且使多次散射计算的射线跟踪速度加快。计算机模拟计算结果表明，提出的新技术是有效的，本文的多层Ｚ缓冲器技术可应用于其它研究领域。     

Casting shadows with approximated object space accuracy by means of a modified Z-buffer

Shadows are important in enhancing both the realism and the intelligibility of synthetic 2D images of 3D scenes. In order to determine which part of a scene is in shadow, numerous algorithms have been developed. The Z-buffer shadow algorithm and its descendants have proved to be both efficient and easy to implement. However, in casting shadows, the aliasing introduced by the Z-buffer point sampling is notorious. Therefore a new method that is based on a modification of the Z-buffer has been developed. This method deals with the aliasing problem but preserves the strengths of the Z-buffer algorithm. Moreover, as a side effect, the information stored in the modified Z-buffer allows accurate antialiasing of the resulting image.     

Techniques for accelerating B-rep based parallel machining simulation

Continued progress in the area of solid modeller based machining process simulation is hindered by the complexity growth that occurs for a large number of tool-paths, n. For this reason, many researchers have adopted the Z-buffer approach. Boundary-representation (B-rep), however, remains the dominant choice for commercial computer aided design and manufacturing software. In this paper, it is shown that, under practical 2 1/2 D machining assumptions, the total number of tool-path neighbour pairs is O(n), and therefore the average ratio of simulated to subtracted tool-paths remains constant. Tool-path neighbours are grouped and simulated in parallel, greatly reducing wall clock running time. Running time is further reduced by filtering the intersection graph for edges and faces that are relevant to the cutter immersion. This information is subsequently used to discard irrelevant and time consuming intersection operations. Overall, a 90% decrease in wall clock running time was achieved.     

Data-parallel,volumerendering algorithms

In this presentation, we consider the image-composition scheme for parallel volume rendering in which each processor is assigned a portion of the volume. A processor renders its data by using any existing volume-rendering algorithm. We describe one such parallel algorithm that also takes advantage of vector-processing capabilities. The resulting images from all processors are then combined (composited) in visibility order to form the final image. The major advantage of this approach is that, as viewing and shading parameters change, only 2D partial images, and not 3D volume data, are communicated among processors. Through experimental results and performance analysis, we show that our parallel algorithm is amenable to extremely efficient implementations on distributed memory, multiple instruction-multiple data (MIMD), vector-processor architectures. This algorithm is also very suitable for hardware implementation based on image composition architectures. It supports various volume-rendering algorithms, and it can be extended to provide load-balanced execution.     

基于可见性预处理和细节简化的虚拟环境快速漫游算法

本文针对复杂多边形场早的漫游提出了一个新的预处理方法，并给出了相应的快速漫游算法。     

Two-level hierarchical Z-buffer with compression technique for 3D graphics hardware

The hierarchical Z-buffer is application-invisible and more efficient than the traditional Z-buffer for quickly rejecting hidden geometries. But there are construction and management issues associated with integrating a hierarchical Z-buffer into current graphics hardware. Here we present a two-level hierarchical Z-buffer algorithm, and provide solutions to these issues. Simulation results show that the bandwidth can be reduced by up to 35%. Moreover we propose a dynamic bi-level HZ-buffer compression technique that reduces the buffer size up by to 40%, and for which there is little performance degradation.     

三维图形显示系统的图形消除器和象素处理器技术实现

图形消隐器和象素处理器是三维图形显示系统的重要组成部分。讨论了图形消除器和象素处理器的算法,结合具体的硬件电路提出了实现设计的思路,实践应用表明了这种设计的可行性。     

基于OpenGL三维非均匀FDTD网格图形的消隐处理*

在分析了三维非均匀FDTD网格图形性质及计算数据结构特点的基础上,提出了一种基于OpenGL深度缓冲机制的绘图方法,采用多边形深度偏移量修正法进行精细化的消隐修正,实现了网格图形的快速生成与高效消隐,大大提高了FDTD仿真及模拟计算网格图形的可视化效果,并在此基础上设计并实现了基于OpenGL的三维网格模型仿真系统.最后,以U型天线的网格图形为例,展示其可视性.